Clinical characteristics and risk factors of arrhythmia during follow‐up of patients with idiopathic ventricular fibrillation

Abstract

Aims: The current knowledge of idiopathic ventricular fibrillation (IVF) is limited. We aimed to investigate the nature of IVF, including clinical assessment and later diagnosis, and risk factors of implantable cardioverter defibrillator (ICD) therapy in the follow-up period. Methods: Between 2007 and 2019 we systematically identified all patients from Rigshospitalet, Denmark, with a resuscitated sudden cardiac arrest (SCA) with no identifiable cause. All patients were followed routinely in the ICD outpatient clinic and the majority also in an inherited heart disease outpatient clinic. Outcomes were analysed with Cox regressions models and cumulative incidence curves. Results: We identified 84 patients with an initial diagnosis of IVF; of these, three (3.6%) patients were later diagnosed with a cardiac disease. The remaining IVF patients (n = 81, median age 45 years; men 71.6%) were followed a median follow-up of 5.2 years (interquartile range, 2.0-7.6). A total of 24 (29.6%) patients had appropriate ICD therapy and 12 (14.8%) patients had inappropriate ICD therapy. No predominant type of ventricular arrhythmia at first appropriate ICD therapy was observed. Early repolarization at baseline was not associated with an increased risk of appropriate ICD therapy (P = .842). Repeated cardiac arrest at index SCA increased the risk of appropriate ICD therapy (hazard ratio, 2.63 [95% CI, 1.08-6.40; P = .033]). Conclusion: Most patients remained idiopathic throughout the follow-up period and the overall long-term prognosis of IVF was good. Repeated cardiac arrest at index SCA was a risk factor of appropriate ICD therapy and early repolarization was not associated with an increased risk of appropriate ICD therapy.

2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death

“…In particular the significance of detected early repolarization pattern (ERP) in asymptomatic relatives is uncertain. 182,916 In IVF patients, ICD implantation reduces the risk of arrhythmic death by up to 68% compared to amiodarone 352,[917][918][919][920][921] (Figure 27). In observational studies with a mean follow-up of 5-6 years, 21.0-29.6% of IVF patients experienced an arrhythmic recurrence, corresponding to an annual ICD shock rate of 3.6-5.7%, whereas 4.5-17.5% experienced inappropriate shocks.…”

“…In observational studies with a mean follow-up of 5-6 years, 21.0-29.6% of IVF patients experienced an arrhythmic recurrence, corresponding to an annual ICD shock rate of 3.6-5.7%, whereas 4.5-17.5% experienced inappropriate shocks. [919][920][921] Isoproterenol, verapamil, or quinidine have been employed for acute treatment of recurrent ICD discharges or electrical storm. 912,913,918,[922][923][924][925][926] In several small studies, quinidine was highly effective in reducing or even preventing arrhythmia inducibility during programmed stimulation.…”

“…249,278,914,915 IIb B Secondary prevention of SCD and treatment of VA ICD implantation is recommended in idiopathic VF. 352,[917][918][919]…”

State-of-the-Art Multimodality Imaging in Sudden Cardiac Arrest with Focus on Idiopathic Ventricular Fibrillation: A Review

“…The initial work-up influences the diagnostic yield of the additional tests, resulting in different yields between SCA survivors (with limited diagnostic testing) compared to UCA survivors. When reviewing available cohort studies focusing on either UCA or IVF patients, it stands out that the performed diagnostic work-up is often not complete ( Tables S2 and S3 ) [ 4 , 5 , 17 , 18 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ]. An incomplete diagnostic work-up leads to an inconsistent use (and possible overuse) of the terminology IVF in current literature [ 15 ].…”

“…Compared to echocardiography and CMR, cardiac CT is less frequently performed in diagnosed IVF patients [ 4 , 5 , 21 ]. With this infrequent use of cardiac CT in IVF cohorts, the diagnostic value remains unknown.…”